lws-err-detail

Middleware plugin for lws to include the error stack trace in the HTTP response. Always use as the first middleware in the stack.

In this example, broken.js is a middleware which throws an exception.

$ lws --stack lws-err-detail broken.js
Listening on http://mba4.local:8000, http://127.0.0.1:8000, http://192.168.0.200:8000

Without lws-err-detail, the response does not include any information about the error.

$ curl -i http://localhost:8000
HTTP/1.1 500 Internal Server Error
Content-Type: text/plain; charset=utf-8
Content-Length: 21
Date: Fri, 21 Jun 2019 14:27:58 GMT
Connection: keep-alive

Internal Server Error

With lws-err-detail at the top of the middleware stack, the response now includes the exception stack trace.

$ curl -i http://127.0.0.1:8000
HTTP/1.1 500 Internal Server Error
Content-Type: text/plain; charset=utf-8
Content-Length: 838
Date: Fri, 21 Jun 2019 10:13:06 GMT
Connection: keep-alive

Error: broken
    at /Users/lloyd/Documents/lwsjs/err-detail/broken.js:4:13
    at dispatch (/Users/lloyd/Documents/lwsjs/local-web-server/node_modules/koa-compose/index.js:42:32)
    at /Users/lloyd/Documents/lwsjs/err-detail/index.js:9:15
    at dispatch (/Users/lloyd/Documents/lwsjs/local-web-server/node_modules/koa-compose/index.js:42:32)
    at /Users/lloyd/Documents/lwsjs/local-web-server/node_modules/koa-compose/index.js:34:12
    at Application.handleRequest (/Users/lloyd/Documents/lwsjs/local-web-server/node_modules/koa/lib/application.js:151:12)
    at Server.handleRequest (/Users/lloyd/Documents/lwsjs/local-web-server/node_modules/koa/lib/application.js:133:19)
    at Server.emit (events.js:200:13)
    at parserOnIncoming (_http_server.js:713:12)
    at HTTPParser.parserOnHeadersComplete (_http_common.js:116:17)err-detail

The lws command line tool will always write error details to the console.